Epidermis & Keratinization

Question 1

Squamous cell carcinoma characterized by?

Answer 1

Redness and scaling

Question 2

Row of tombstones is indicative of?

Answer 2

Pemphigus vulgaris

Question 3

Desquamation involves? (3 things)

Answer 3

1) Proteolysis of intercellular bonds via hydrolases
2) Organized dissolution of intercellular lipids
3) Keratinocytes shed singly without dry skin

Question 4

Xerosis characterized by? (3 things)

Answer 4

Fine, white scale
Hyperkeratosis
May be itchy

Question 5

Mechanism of xerosis (3 things)

Answer 5

1) Dehydration of keratinocytes due to decrease in Natural Moisturizing Factors
2) Decreased intercellular lipids
3) Failure to break intercellular bonds in organized fashion

Question 6

5 endogenous causes of xerosis

Answer 6

Atopy
Ichthyosis vulgaris
Renal insufficiency
Lipid lowering medications
Malnutrition

Question 7

Acanthosis

Answer 7

Hyperplasia of stratum spinosum due to proliferation

Question 8

Hyperkeratosis

Answer 8

Hyperplasia of corneum due to increased production or reduced desquamation

Question 9

Lichenification

Answer 9

Hyperplasia of spinosum and corneum due to scratching / rubbing

Question 10

Keratosis pilaris

Answer 10

Hyperkeratosis (hyperplasia of corneum) due to retention

Tiny pink dots associated w/ hair follicles

Question 11

Lichen simplex chronicus

Answer 11

Lichenification (hyperplasia of spinosum and corneum) due to rubbing and scratching

Question 12

Ichthyosis vulgaris (cause, inheritance, age, appearance, association)

Answer 12

Most common disorder of cornification
Retention hyperkeratosis
Autosomal dominant
Appears in childhood
Fish scale appearance (polygonal)
Associated with atopic triad, hyperkeratosis pilaris, and hyper linear palms

Question 13

Palmoplantar Keratoderma (cause, inheritance, 3 subtypes, and treatment)

Answer 13

Hyperkeratosis of palms and soles
Autosomal dominant and recessive
Due to keratin mutation
Diffuse - thick, yellow plaques; associated w/ hyperhidrosis (excess sweating)
Focal - Hyperkeratosis over pressure points
Punctate - Hyperkeratotic papules w/ warty apperance
Treated w/ paring hyperkeratotic areas, moisturizers, and humectants

Question 14

Atopic dermatitis (cause, defect, sxs, tx)

Answer 14

Inflammation due to aberrant TH2 response
Filaggrin defect –> reduction in AA’s –> dehydration of corneum
Itchy rash that favors flexural surfaces
Treat with topical steroid

Question 15

Psoriasis (inflammation, sxs, tx)

Answer 15

Inflammation due to TH1 and TH17
Hyperplasia of spinosum (acanthosis) due to increased rate of cell turnover and inflammation
Variably itchy rash that favors extensor surfaces
Red plaques, thick adherent scale, and nail changes.
Tx w/ topical steroid

Question 16

Atopic dermatitis (cause, defect, sxs)

Answer 16

Inflammation due to aberrant TH2 response
Filaggrin defect –> reduction in AA’s –> dehydration of corneum
Itchy rash that favors flexural surfaces

Question 17

Psoriasis (inflammation and sxs)

Answer 17

Inflammation due to TH1 and TH17
Faster cell turnover
Variably itchy rash that favors extensor surfaces
Red plaques, thick adherent scale, and nail changes.

Question 18

SSSS (cause, sxs, treatment)

Answer 18

Due to exotoxin of staph aureus (Exofoliative toxins ET-A / B) attacking desmoglein 1
Toxins are renally excreted
Malaise, irritability, fever, PAIN
Cutaneous erythema starting at head and generalizing
Flacid bullae
Desquamation
Tx includes IV antibiotics

Question 19

5 steps of keratinization

Answer 19

1) Enlargement and flattening of keratinocytes
2) Filaggrin-induced keratin assembly and cross-linking to form cornfield envelop
3) Lamellar granule lipids form hydrophobic barrier
4) Degradation of organelles to form anucleate cells
5) Apoptosis
Moving upwards the whole time